Separator for lithium secondary battery

Abstract

A separator for a lithium secondary battery includes a coating layer including an organic/inorganic bindable silane compound having a reactive functional group, the reactive functional group being selected from the group consisting of amino groups, isocyanate groups, epoxy groups, mercapto groups, and combinations thereof; and an inorganic compound. The separator has excellent high temperature stability.

What is claimed is: 
     
         1 . A separator for a lithium secondary battery, the separator comprising:
 a coating layer comprising:
 an organic/inorganic bindable silane compound having a reactive functional group, the reactive functional group being selected from the group consisting of amino groups, isocyanate groups, epoxy groups, mercapto groups, and combinations thereof; and 
 an inorganic compound. 
   
     
     
         2 . The separator of  claim 1 , wherein the coating layer comprises a surface coating formed on a surface of the inorganic compound by the organic/inorganic bindable silane compound. 
     
     
         3 . The separator of  claim 2 , wherein the surface coating is continuous or discontinuous. 
     
     
         4 . The separator of  claim 1 , wherein the organic/inorganic bindable silane compound having the reactive functional group is selected from the group consisting of epoxyalkylalkoxysilanes, aminoalkylalkoxysilanes, isocyanato alkylalkoxysilanes, mercapto alkylalkoxysilanes, and combinations thereof. 
     
     
         5 . The separator of  claim 1 , wherein the organic/inorganic bindable silane compound having the reactive functional group is selected from the group consisting of vinylalkylalkoxysilanes, halogenated alkylalkoxysilanes, vinylhalosilanes, alkylacyloxysilanes, and combinations thereof, and wherein the vinylalkylalkoxysilanes, halogenated alkylalkoxysilanes, vinylhalosilanes, alkylacyloxysilanes, and combinations thereof comprise the reactive functional group selected from the group consisting of amino groups, isocyanate groups, epoxy groups, mercapto groups, and combinations thereof. 
     
     
         6 . The separator of  claim 1 , wherein the inorganic compound is selected from the group consisting of SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , BaTiO 3 , SiO 2 , and combinations thereof. 
     
     
         7 . The separator of  claim 1 , wherein the coating layer of the separator further comprises a binder selected from the group consisting of polyvinylidenefluoride (PVdF), poly(vinylidene-hexafluoropropylene) (P(VdF-HFP)), a modified PVDF with COOH, polyethyleneoxide (PEO), polyacrylonitrile (PAN), polyimide (PI), polyamic acid (PAA), polyamideimide (PAI), aramid, polyvinylacetate (PVA), polymethylmethacrylate (PMMA), polyvinylether (PVE), and combinations thereof. 
     
     
         8 . The separator of  claim 1 , wherein the separator further comprises a porous substrate selected from the group consisting of glass fiber, polyester, tetrafluoroethylene, polyolefin, polytetrafluoroethylene (PTFE), and combinations thereof. 
     
     
         9 . The separator of  claim 7 , wherein the coating layer of the separator is formed on one side or both sides of the porous substrate. 
     
     
         10 . The separator of  claim 1 , wherein the coating layer of the separator comprises about 1 part by weight to about 20 parts by weight of the organic/inorganic bindable silane compound having the reactive functional group, based on 100 parts by weight of the inorganic compound. 
     
     
         11 . The separator of  claim 6 , wherein the coating layer of the separator comprises the inorganic compound and the binder in a weight ratio in a range of about 1:0.5 to about 1:5. 
     
     
         12 . The separator of  claim 1 , wherein the organic/inorganic bindable silane compound having the reactive functional group is selected from the group consisting of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, (3-trimethoxysilylpropyl)diethylenetriamine, (2-aminoethyl)-3-aminopropyltrimethoxysilane, N-methylaminopropyltrimethoxysilane, 3-(triethoxysilyl)propyl isocyanate, 3-(trimethoxysilyl)propyl isocyanate, 3-mercaptopropyltrimethoxysilane, bis(3-(triethoxysilyl)propyl)-tetrasulfide, vinyltris (2-methoxy ethoxy) silane, 3-methacryloxylpropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, vinyltrichlorosilane, methyltriacetoxysilane, and combinations thereof. 
     
     
         13 . A rechargeable battery comprising:
 a positive electrode;   a negative electrode; and   the separator of  claim 1  between the positive electrode and the negative electrode.   
     
     
         14 . The battery of  claim 13 , wherein the coating layer comprises a surface coating formed on a surface of the inorganic compound by the organic/inorganic bindable silane compound. 
     
     
         15 . The battery of  claim 13 , wherein the organic/inorganic bindable silane compound having the reactive functional group is selected from the group consisting of epoxyalkylalkoxysilanes, aminoalkylalkoxysilanes, isocyanato alkylalkoxysilanes, mercapto alkylalkoxysilanes, and combinations thereof. 
     
     
         16 . The battery of  claim 13 , wherein the organic/inorganic bindable silane compound having the reactive functional group is selected from the group consisting of vinylalkylalkoxysilanes, halogenated alkylalkoxysilanes, vinylhalosilanes, alkylacyloxysilanes, and combinations thereof, and wherein the vinylalkylalkoxysilanes, halogenated alkylalkoxysilanes, vinylhalosilanes, alkylacyloxysilanes, and combinations thereof comprise the reactive functional group selected from the group consisting of amino groups, isocyanate groups, epoxy groups, mercapto groups, and combinations thereof. 
     
     
         17 . The battery of  claim 13 , wherein the inorganic compound is selected from the group consisting of SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , BaTiO 3 , SiO 2 , and combinations thereof. 
     
     
         18 . The battery of  claim 13 , wherein the coating layer of the separator comprises about 1 part by weight to about 20 parts by weight of the organic/inorganic bindable silane compound having the reactive functional group, based on 100 parts by weight of the inorganic compound. 
     
     
         19 . The battery of  claim 13 , wherein the organic/inorganic bindable silane compound having the reactive functional group is selected from the group consisting of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, (3-trimethoxysilylpropyl)diethylenetriamine, (2-aminoethyl)-3-aminopropyltrimethoxysilane, N-methylaminopropyltrimethoxysilane, 3-(triethoxysilyl)propyl isocyanate, 3-(trimethoxysilyl)propyl isocyanate, 3-mercaptopropyltrimethoxysilane, bis(3-(triethoxysilyl)propyl)-tetrasulfide, vinyltris (2-methoxy ethoxy) silane, 3-methacryloxylpropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, vinyltrichlorosilane, methyltriacetoxysilane, and combinations thereof. 
     
     
         20 . The battery of  claim 13 , wherein the coating layer of the separator further comprises a binder, and wherein the coating layer of the separator comprises the inorganic compound and the binder in a weight ratio in a range of about 1:0.5 to about 1:5. 
     
     
         21 . A method of forming a rechargeable battery, the method comprising:
 forming the separator of  claim 1 , a positive electrode, and a negative electrode into an electrode assembly; and   providing an electrolyte to the electrode assembly.